A weevil is a small beetle — usually just a few millimetres long — with a long snout sticking out from its head, and it is a pest of stored food and crops. Weevils get into rice, flour, wheat, beans and dried noodles: you open the bag, and there they are, small brown or black specks moving. That is why the word appears so often in a kitchen context rather than a nature one. There are thousands of kinds, and the ones people name are named after what they ruin: rice weevil, grain weevil, boll weevil (which destroyed cotton farms across the American South, and is famous enough to appear in blues songs and history books). Two things to notice about how English uses this word. First, it is a proper name for a kind of insect, not a general word for "bug in my food" — but ordinary speakers use it loosely for any tiny beetle found in a rice bag, whether or not it truly has the snout. Second, `weevil` has an old figurative pull: because weevils eat away quietly from inside a store of food, writers sometimes use the image for something small that slowly ruins something large from within. That use is uncommon and literary; don't reach for it in speech. Plural is regular: weevils. The word is neutral in tone — no politeness problem — but it is not a common everyday word for most people; a Taiwanese student is more likely to need it when reading about food storage or farming than in chat.